fritzthemoose Posted December 27, 2012 Share Posted December 27, 2012 Just got myself a RRA 9mm Upper for my AR. Anyone any experience if a comp works on an 16 inch barrel or would it be useless? Not sure if there is enough gas left even with a major load for the comp to work. Link to comment Share on other sites More sharing options...
Alaskapopo Posted December 27, 2012 Share Posted December 27, 2012 Well it can't hurt. I wonder though if porting the barrel as far back as you can depending on how long your handguard is would do better. Its a blow back so losing gas should not affect function. Like a hybrid barrel on a handgun but on your rifle instead. Pat Link to comment Share on other sites More sharing options...
THM7 Posted December 28, 2012 Share Posted December 28, 2012 There was a thread on this subject on one of the Subgun forums a while back. I have messed with comps on various 9mm carbines and SMG's and they did very little for muzzle rise. What does seem to work is a Suppressor.....but thats a different subject. www.uzitalk.com and www.bullethose.com might have some info for you. Link to comment Share on other sites More sharing options...
Sonoma820 Posted December 28, 2012 Share Posted December 28, 2012 Although I have not fired a AR type 9mm carbine I have shot lots of MP5! I don't think it would make any difference. Recoil and muzzle rise are almost nonexistent on a 9mm carbine. I have fired lots of full auto through an MP5 which are not equipped with muzzle devises and it does not seem to be a real problem. Good grip and stance does plenty to control it sufficiently most of the time and that is while shooting full auto. I would spend the same money practicing. Link to comment Share on other sites More sharing options...
Larry White Posted December 28, 2012 Share Posted December 28, 2012 9mm carbines are blow back actions. most of the recoil and gun movement comes fron that heavy ass bolt siaming back and forth. a comp wont help enough to notice.----------Larry. Link to comment Share on other sites More sharing options...
StealthyBlagga Posted December 28, 2012 Share Posted December 28, 2012 A few years ago I performed an experiment where I quantified the shot dispersion of 2-shot bursts from an open bolt submachine gun with and without a compensator (the Carlson Compensator, which everyone was raving about at the time). Testing was extensive versus a birdcage flash hider as the control. The compensator provided no measurable benefit. As mentioned above, there is very little gas, even out of a 10" barrel, and any compensation effect is dwarfed by the heavy bolt slamming back and forth. The best way to reduce recoil impulse on a pistol caliber carbine is to go to a gas operated system. Unfortunately they are EXTREMELY difficult to make run, and typically require handloaded ammo to ensure the right type of gas impulse. They are apparently commercially available at http://www.rmwxtreme.com/, though not sure about 9mm. Link to comment Share on other sites More sharing options...
PursuitSS Posted December 28, 2012 Share Posted December 28, 2012 My wife ran a Comp (S&H of Oklahoma) on her competition HK MP-5. She was convinced it helped her win the Fall 1997 Knob Creek Sub Gun Open. I couldn't tell any difference, but then again, I wasn't "dialed in" like she was. She was able to fire single shots regularly while on Full Auto. (Cyclic rate - 820 rpm) Link to comment Share on other sites More sharing options...
Stlhead Posted December 28, 2012 Share Posted December 28, 2012 They may not help, but they sure look cool! Link to comment Share on other sites More sharing options...
Alaskapopo Posted December 28, 2012 Share Posted December 28, 2012 Although I have not fired a AR type 9mm carbine I have shot lots of MP5! I don't think it would make any difference. Recoil and muzzle rise are almost nonexistent on a 9mm carbine. I have fired lots of full auto through an MP5 which are not equipped with muzzle devises and it does not seem to be a real problem. Good grip and stance does plenty to control it sufficiently most of the time and that is while shooting full auto. I would spend the same money practicing. Actually in my experience from owning a 9mm RRA carbine and a lot of .223 carbines the 9mm's kick more due to the blow back action. Its like how a .380 blow back pistol will kick more than a 9mm locked breach gun of the same size. Plus in the game and in real life you can't always have a perfect stance or grip while your leaning around a barricade shooting a target at a akward angle. People know that you have to practice but there is also a value in a good comp. Pat Link to comment Share on other sites More sharing options...
fritzthemoose Posted December 29, 2012 Author Share Posted December 29, 2012 yes the blow back is heavy ineed compared to the 223. Which buffer are u running in 9mm compared to the 223`? Link to comment Share on other sites More sharing options...
THEJACKO Posted December 30, 2012 Share Posted December 30, 2012 My 9mm has a spikes buffer with 9mm spacer for buffer tube spring. I use it side by side with my 223 ( mid length gas ) and they feel the same. I do notice spring noise from my 9mm. Link to comment Share on other sites More sharing options...
Alaskapopo Posted December 30, 2012 Share Posted December 30, 2012 yes the blow back is heavy ineed compared to the 223. Which buffer are u running in 9mm compared to the 223`? I was running the 9mm buffer which is way heavier. Pat Link to comment Share on other sites More sharing options...
m134b Posted December 30, 2012 Share Posted December 30, 2012 Ramping the 9mm bolt will help smooth things out a little bit, It helps on the semis as well, not just F/A 9mm AR's. M60Joe does excellent work, as do several other 'smiths. Ken Link to comment Share on other sites More sharing options...
Stony Lane Posted December 30, 2012 Share Posted December 30, 2012 My 9mm has a spikes buffer with 9mm spacer for buffer tube spring. I use it side by side with my 223 ( mid length gas ) and they feel the same. I do notice spring noise from my 9mm. I've read that 7 quarters placed behind the buffer tube spring does the same thing as the spacer. (and only costs $1.75.) I plan to try it. Link to comment Share on other sites More sharing options...
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